Estimativa da geração de uma unidade fotovoltaica baseada na modelagem de uma célula utilizando valores da folha de dados

Abstract

The use of renewable energy sources is the focus of contemporary discussions, given the finite character and impacts that not renewable traditional sources cause to the environment. Among the main renewable energy sources, solar energy is one of the most outstanding, especially in Brazil, which has enormous potential. Although its cost has fallen considerably last years, it is still considered high, therefore, it is indispensable that the system sizing be performed correctly, because carelessness at this stage influences the financial viability of the investment. Therefore, the need to test one of the most widely used system sizing techniques, the solar insolation. This was possible by developing a computational routine to estimate the energy generated by the system considering data of irradiance and temperature real collected experimentally in the city of João Pessoa / PB. The routine is based on the modeling of photovoltaic cells in the form of electrical circuits that use experimental data made available in the manufacturers’ data sheets. We present four methodologies that present methods for solving the proposed equation, each of the methods based on the development of algorithms that characterized the modules in the form of current and voltage curves. The estimates were then compared to the experimental curves provided by the manufacturers and analyzed by absolute error and relative error calculated point to point, in addition to the mean square error. Based on the relationship between precision and complexity, one of the methodologies was chosen to continue the development of the study, which consisted in estimating the energy generated by the system under real conditions. The chosen methodology was improved by varying the ideality factor, resulting in improved precision, and simplicity by subjecting it to different modules. The improved methodology was used to simulate the behavior of an experimentally mounted photovoltaic system containing 14 modules, and subjected to temperature and irradiance values measured experimentally by a meteorological measurement station assembled in the same locality of the test photovoltaic system. The simulation considered only the photovoltaic modules, and had as answer, at the different input values, current and power curves at the output of the system, which could be converted into energy generated, estimated in the period of the 31st day of August 2016, with registers registered every 10 minutes. The results obtained, in the form of energy generated, by the simulation based on the improved methodology were compared with the energy estimates obtained from the simulation based on the methodology of less precision and with the estimation obtained through the use of the insolation method. These results can also be compared or validated with the actual amount of energy generated by the experimentally mounted system. The analysis proposed by this study serves to understand how changes in the modeling, parameterization and characterization of a photovoltaic cell can effectively influence the estimated results for the amount of energy generated by the system, as well as verify the effectiveness of traditional methods such as the method To generate reliable estimates that will provide the correct sizing of the system.